Tech Turns Air Into a Multi-Touch Screen

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Touch-sensitive frames have enabled surfaces to become
interactive for years, but their size and responsiveness tend to
be limited. A new prototype called "ZeroTouch" might look like an
empty frame, but it's actually full of advanced capabilities.

The 28-inch ZeroTouch frame with scalloped edges can detect
whatever moves around inside it. Fingertips, hands, arms, and
even inanimate objects pass through an invisible two-dimensional
optical web that tracks them. Put ZeroTouch on a computer screen
and it turns into an interactive surface that can be manipulated
with a stylus.

"What we can do is very precise sensing inside a specific plane
of interaction," said Jon Moeller, a research assistant at Texas
A&M's Interface Ecology Lab who collaborated with fellow
research assistant Sashikanth Damaraju and lab director Andruid
Kerne on the technology.

The technology itself is straightforward. The ZeroTouch frame
contains 256 infrared sensors and 32 LEDs, and each light blinks
at a specific frequency that is read in sequence by the sensors.
The prototype is so responsive because each LED is blinked in
sequence about 2,400 times a second, Moeller said. The frame is
connected to a computer via USB, which provides power and
collects the data.

"When you combine all the perspectives together, you get this
sort of mesh that gives you the visual hull [the shape produced
from two silhouette images] of any objects that are inside that
touch area," Moeller said.

The researchers presented ZeroTouch this week in Vancouver at the
ACM CHI Conference on Human Factors in Computing Systems. They
suspended one frame in midair where movements made inside the
frame created colorful brushstrokes projected on a wall.

One big advantage to ZeroTouch, the researchers say, is its
affordability. The research prototype was made using commercially
available sensors usually found in TV remote controls. Moeller
said that the frame, which wasn't designed for mass-production,
cost about $450 to construct.

Kerne said that ZeroTouch has many potential applications such as
a training guide for surgeons that can track their fine hand
movements, as well as for interactive instructions on how to
construct complicated machinery.

Moeller pointed out that the technology creates more
possibilities for interaction than capacitive interfaces like the
glass touch-screens on smart phones and laptops. The technology
simply requires the user to break the light beams -- there's no
force required to activate the sensor.

"You can use it with gloves on," Moeller said. "So it can be used
in hazardous environments where capacitive would be unsuitable."

Next, the team plans to work on making the technology larger and
three dimensional, Kerne said. They will experiment to find out
what kind of interactive potential can be achieved by stacking
layers of the frames.

Daniel Wigdor, an assistant professor of computer science at the
University of Toronto who specializes in user interfaces,
interacted with ZeroTouch technology at the conference in
Vancouver.

"It tracks very quickly," he said. "You can detect a very large
number of touches, whereas previous implementations have limited
this to one or two fingers."

Ben Bederson, a human-computer interaction expert and computer
science professor at the University of Maryland, also tried out
the technology. "It doesn't feel like anything, which is just
about right," he said.